1. Field of the Invention
The present invention relates to water purification apparatus which is particularly, but not exclusively, applicable to purification of water in swimming pools.
2. The Prior Art
It is known that certain metal ions have purifying properties when present in water. It has been established that silver ions are extremely effective at controlling the growth of bacteria populations, and similarly that copper ions act as an efficient algicide.
There have been various proposals to provide apparatus adapted to purify water by the introduction of metal ions into water. However, it is not believed that any of the proposals have resulted in comercially acceptable apparatus. Referring to e.g., U.S. Pat. No. 3,092,566; British Pat. No. 1,331,308; British Pat. No. 950,482 and British Pat. No. 950,481 it is noticeable that while the constructions are described in detail, operating parameters are not generally given. It is believed that the operating parameters of the apparatus are of paramount importance for the following reasons.
The efficiency of silver and copper ions for purification is well documented and has been known since Roman times. However, it is believed that the very efficiency of these ions for purification purposes has led previous constructors of apparatus to use levels of concentration of the ions in water which are too low, which in turn has led them to use very low currents for the release of the ions.
It is believed that this rendered previous apparatus susceptible to variations in the conductivity of the water to be purified with consequent deleterious results.
It is an object of the present invention to provide apparatus adapted to reliably purify water by introduction of metal ions into the water using an electrolytic process.